If you're a woman who has a yeast infection and you have sex with your boyfriend then yes it is possible to pass the yeast infection to your boyfriend through the sex.
When your boyfriend inserts his penis into your vagina and you have a yeast infection it's possible for the man to get the yeast infection on his penis.
However the worst of the yeast infection that would happen to your boyfriend is a rash on his penis that can go away with treatment or even on it's own.
You can soak in a tub of warm water with apple cider vinegar to help kill off yeast infections and your boyfriend if he gets the yeast infection on his penis then he can also soak in a tub of warm bath water along with some apple cider vinegar.
Or apply some apple cider vinegar directly to the penis rash yeast infection.
You can also get some cream through a doctor or over the counter to help kill the bacteria causing a yeast infection.
But if you do have a yeast infection it's best to stop having any sex with your partner until your yeast infection has gone away.